1. Field of the Invention
The invention relates in general to a personal digital assistant (PDA), and more particularly to a personal digital assistant with static electricity preventing function.
2. Description of the Related Art
Static electricity originates from the contact and separation between two objects. When the two objects come into contact with each other, electrons will shift from one object to the other. When the two objects separate from each other, the object with electrons departing away will carry positive charge whereas the electron-receiving object will carry negative charge. A tiny amount of electrons, say, as small as a few hundred thousandth of the total amount, shifting from one object to the other would suffice to produce a significant electrostatic effect. Normally, the drier the environment is, the easier the electrostatic phenomenon becomes consequently. Electrostatic discharge (ESD) effect means the discharge effect caused by the ionization of gas around the electric field formed by the object with positive charge. Discharge phenomenon is due to dielectric breakdown, which occurs as long as the strength of electric filed formed by a charged body reaches the critical level of dielectric breakdown. By means of grounding and bonding, the easiest but most effective way to prevent electrostatic discharge, the charges generated will be channeled and dispersed immediately. If there are more than two objects carrying static electricity, the potential difference between them can be reduced if they are connected via a conductor and are grounded. As a consequence, the discharge effect between different objects can be avoided.
In recent years the electronic industry is booming around the world, and the market demand for portable electronic appliances such as notebook computers, mobile phones, personal digital assistants etc. is mounting. Meanwhile, due to the improvement in living standard, people nowadays tend to have air conditioning equipment installed both in their workplaces and homes as well to lower the humidity such that a more comfortable living environment can be attained. However, a dry environment makes it difficult to eradicate static electricity. The semi-conductor components inside electronic products such as personal digital assistants are apt to be influenced by static electricity, causing damage to the product itself. A conventional personal digital assistant can bear up to 10 KV of electrostatic discharges. Therefore, how to strengthen the static electricity preventing function of electronic products so as to prevent them from being afflicted by electrostatic discharges has become a problem of immediate concern for engineers.